In conventional four-stroke internal combustion engines, techniques such as turbocharging (exhaust driven blower) or supercharging (power driven blower) have been advanced for achieving compression of the inlet air, in order to obtain more power. Although such techniques have been used for many years, they remain relatively expensive. And, in the case of turbocharging, heat resistant materials are necessary for the exhaust side, and such materials are available only at significant capital expense.
Consequently, there remains a significant and as yet unmet need for a four-stroke engine which provides a significant boost in power, but without the complexity and expense of heretofore known turbocharging or supercharging techniques.